1. Field of the Invention
This invention relates generally to systems and methods for enabling one structure to be attached and/or pivotably moved relative to another structure and, more particularly, to attachment assemblies of the pinless hinge type configured to both pivotably and releasably couple such structures.
2. Discussion of the Background Art
In its most familiar form, a hinge includes a pair of hinge halves with each hinge half including a wing section and a half channel coupled to the wing section. When the half channels of the hinge halves are aligned, the half channels form a pivot channel for receiving a separate pivoting pin. When the wing sections are attached to respective objects or structures, such as a door and a door frame, an awning and wall structure, a lid and container, or even a picture frame strut to a picture frame, the structures are able to move pivotably with respect to each other about the pivoting pin. There are a number of disadvantages associated with the “standard” pin-type or three-piece hinge. These include the relatively high cost of forming accurately aligned and well-fitted openings for receiving the pin, susceptibility to malfunction from dirt or corrosion, and the fact that the pin itself may be broken, displaced or lost altogether.
A further disadvantage of the pin-type hinge is most readily appreciated in certain contexts, such as when one (or each) of the wing sections is attached to a large, heavy, and/or unwieldy structure. When a conventional hinge is used for such situations, it is difficult to align the two hinge halves long enough to insert the pin. An individual working alone with pin-type hinges may find the task of pivotably coupling such cumbersome structures to be very difficult or even impossible. The process of detaching one structure from another can be equally laborious to an individual working alone.
A number of alternatives to the conventional three-piece (pin-type) hinge have been developed over the years. To simplify the coupling and decoupling of two pivotably attached structures, for example, a variety of so-called “pinless” hinge arrangements have been proposed. While these arrangements vary widely in their configuration and intended applications, they can nonetheless be classified into at least three general categories.
One of the earliest categories of pinless hinge arrangements is the “integral pivot pin” type exemplified by U.S. Pat. No. 678,701 issued to J. B. Tuor on Jul. 16, 1901 and entitled “Separable Hinge”. The two-piece hinge assembly described by Tuor is configured for operation in a substantially vertical plane, and has particular applicability to the hanging of storm sashes and other structures over a framed window opening. An upper wing section has an upper flange section securable to the window frame proximate a lower edge thereof. Downwardly depending from the upper flange section are two channel-forming hooks open at their upper end and laterally separated from one another. The cavities formed by the two hooks define a transverse pivot channel. A lower wing section of the hinge has a lower flange section for attachment to a storm sash or other structure, an integral shank extending upwardly from the lower flange section, and a transverse pivot bar integrally formed at the end of the shank. The integral pivot bar of the second wing section functions as a pivot pin, and the width of the gap formed between the two hooks of the first wing section is such that the shank can move freely within it while leaving the pivot bar supported at both ends by one of its hooks. Removal requires lifting the sash to bring the pivot bar out of registration with the hooks.
One of the principal deficiencies of the Tuor arrangement is that its lower wing section, with its integral shank and transverse pivot bar structure, is complex and expensive to manufacture. Another is that it is difficult to adapt this arrangement to the pivotable coupling of one or more cumbersome objects such, for example, as long shelves or awnings, where alignments of the respective wing sections must be achieved across much wider distances. More substantial deficiencies reside in the fact that the hinge assembly is not self-locking (e.g., the lower wing section of Tuor may easily work loose or become dislodged out of registration with the open channel defined by the upper wing section). Finally, the respective wing sections are strictly adapted for attachment to coplanar vertical surfaces.
Another category of pinless hinge arrangements is the “stationary pivot pin” type exemplified by U.S. Pat. No. 2,644,192 issued to R. E. McClellan on Jul. 7, 1953 and entitled “Detachable Hinge”. The two piece hinge assembly described by McClellan is more or less an adaptation of the Tuor arrangement wherein a first wing section defining the pivot bar is stationary and oriented in a horizontal, rather than a vertical plane, while the pivot channel defined by the second wing section extends from an offset shank attached to the flange. As in Tuor, the pivot axis defined by the pivot bar is oriented in a horizontal axis. A planar structure such as a drop leaf for a desk or table has two of the second wing sections attached two its lower face proximate a lateral peripheral edge. A space, between the desk or table and the fixed pivot axis defined by the pivot bar of respective first wing sections, enables the pivot channel and offset shank of the second wing section to pass through and under the desk surface while the leaf is held inserted at an angle. The leaf is then lowered into a horizontal position and pushed forward so that the surfaces of each pivot bar and each offset shank prevent rotation of the leaf. A locking detent and aperture system prevents lateral translation of the leaf while it is in use. When not needed, the McClellan structure is pivoted slightly to release the locking detent from the aperture, and then the leaf is pulled far enough to bring the respective pivot channels into registration with corresponding pivot bars and fully into the gap. In this position, the leaf can be rotated about the horizontal pivot axis into a vertical position suitable for storage.
The McClellan pinless hinge arrangement suffers from deficiencies similar to the ones noted in connection with Tuor. For example, the McClellan structure is limited to situations in which one of the two pivotably connected structures remains disposed in a horizontal plane. Like Tuor, the McClellan device is not self-aligning but instead requires all mating hinge components to be precisely aligned for proper operation. Also like Tuor, the McClellan device does not permit relative adjustment of the hinge components or associated structures once the hinge components are attached. Neither are the Tuor or McClellan structures well adapted for use by a single installer where large structures are to be pivotably coupled. This is because the spacing between hinge sections secured to one structure is often so great that these sections cannot be aligned with complementary sections on the other structure without help. Finally, the absence of an intrinsically stable locking system means that the drop leaf hinge assembly taught by McClellan cannot be safely adapted to heavier duty applications such, for example, as those where a heavily loaded ancillary structure might pull away from the primary working surface to which it is pivotably secured. If such a structure were to drop down unexpectedly, it could seriously injure workers in the area and/or damage adjacent structures and equipment.
Yet another type of pinless hinge, which may be thought of as the “telescoping” or “extruded” type hinge, includes a first wing section. At one end of the first wing section, a flange is formed, the flange being attachable to a first structure. At the other end of the first wing section is a transverse slotted tube defining both an internal pivot channel and an axial slot. A second wing section has at one end a flange attachable to a second structure and, at the other end, a tubular transverse pivot bar dimensioned and arranged so that it can be inserted laterally in telescoping fashion into the pivot channel while a web region connecting the flange and pivot bar is aligned with the axial slot. The edges of the axial slot act as “stops”, wherein the width of the slot determines the degree to which the second wing section can be rotated about the pivot axis defined by the pivot channel of the first wing section. Representative examples of the telescoping or extruded type of pinless hinge are disclosed in U.S. Pat. No. 2,834,072 issued to Miller on May 13, 1958 and entitled “Awning Structure; in U.S. Pat. No. 3,263,369 issued to Siegal et al. on Aug. 2, 1996 and entitled “Awning Structure”; in U.S. Pat. No. 5,329,667 issued to Erskine on Jul. 19, 1994 and entitled “Pinless Hinge”; in U.S. Pat. No. 5,809,617 issued to Harris et al. on Sep. 22, 1998 and entitled “Mounting for Movable Members”; and in U.S. Pat. No. 6,941,616 issued to Roy on Sep. 13, 2005 and entitled “Pinless Hinge”.
While the extruded or telescoping variety of pinless hinge is less susceptible to unexpected separation than the other categories of hinges described above, certain deficiencies do persist. One disadvantage of the telescoping hinge design is that it is not adaptable to the pivotable connection of large heavy structures. Another is the difficulty of aligning and inserting the smaller of the pivot tubes within the larger one, a problem whose magnitude increases exponentially as the length of the pivot axis increases—especially where lateral clearance and accessibility are limited. Even where lateral access does not impose a constraint, a structure to be pivotable secured relative to another may be so long that an individual installer may be unable to keep the two pivot tubes in alignment long enough to bring them into telescoping alignment. Finally, extrusion is a manufacturing technique well adapted to plastic materials or to softer, ductile metals and metal alloys (e.g., aluminum and brass), its application. However, the application of extrusion processes to materials having requiring greater load bearing ability, strength, wear resistance, and other mechanical properties—may require expensive post-extrusion processes such as annealing, quenching and the like.
Common to all of the aforementioned hinge structures are susceptibility to wear and corrosion, as well as a vulnerability to accidental separation where the objects attached to each hinge section are rotated together to some degree about an axis. Even a three-part hinge is vulnerable, in that the hinge pin can fall out when the entire hinge assembly is inverted (or subjected to centrifugal forces).
A need therefore exists for pinless hinge structures which can quickly self align, self-lock, and self-release, permitting a solo operator to easily actuate any locking mechanism located beyond his or her reach.
A further need exists for pinless hinge structures which can accommodate fail-safe locking structures which are not prone or susceptible to accidental release or separation once engaged.
Another need exists for pinless hinge structures which are impervious to malfunctions commonly caused by corrosion, dirt and debris.
Yet another need exists for pinless hinge structures which can be readily configured and adapted to pivotably couple a wide variety of objects and structures over a range of relative orientations and in a manner which permits the relative positions of these objects to be quickly and easily adjusted.
Still another need exists for an attachment assembly incorporating a pinless hinge structure wherein the hinge structure remains securely locked even when the entire assembly is rotated together to any degree and with respect to any axis of rotation, or when subjected to centrifugal force(s).